This invention relates to an idle stabilizing system for an engine and more particularly to an improved control and fuel injection system for returning the engine smoothly to its idle speed when the throttle is rapidly closed from a high speed condition.
The use of fuel injection systems for maintaining good engine performance, good exhaust emission control and high fuel economy is well known. The control of the fuel injector can permit extremely good performance under a wide variety of running conditions. However, in addition to varying steady state conditions, the fuel injection and its control must provide for good operation and good control of the aforenoted characteristics during transient conditions. One of the most difficult conditions to control is the return to engine idle or low speed operation when the engine has been running at a high speed and the throttle valve is rapidly closed. During this phase of performance, there is a tendency with conventional injected units for the engine speed to reduce very slowly to idle speed with increased fuel consumption and increased HC and CO emissions.
It is, therefore, a principal object of this invention to provide an improved fuel injection system for an engine that will stabilize return to idle speed and assure a quick return to idle speed when closing the throttle from high speed operation.
It is a further object of this invention to provide an improved system and method for operating a fuel injected engine to accelerate the reduction of the engine speed to idle in a quick but smooth manner.